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I replaced a second speaker amp at the other end that also appearing warm and I think its now solved.

I delayed sending this one back to the customer too quickly as I wanted to leave it on the shelf for a few days and make sure it will take a charge. Again it has drained the battery to 0% and won't start charging. Cmizapper battery tool reports TCA and DSG. I tried a new battery too - same...

As a long shot I tried my thermal camera and with only 20mA draw the hottest chip was an audio amp at 30c supplied by 3v8_aon. I lifted it and found corrosion under the chip! Problem solved. Thx for your help.

I tried that. After turning off pp2v5_nand0 the other [20v capable] non-working board still got to 20v. So I suspect this would indicate that reading a NAND partition is not required before going to 20v. Can any other area explain pp3v8_aon oscillating 2.5v to 3.4 avg 3.2v?

Does it need access to the NAND before getting to 20v? This board does not get to 20v.

I do happen to have another non-working board - measurements from this in brackets at end of line pp5v_s2. 0.3v close to OBdata 0.39v pp1v2_s2 0.2v close to OBdata 0.26v pp1v8_s2 0.22v close to OBdata 0.255v pp1v8_aon 0.4v close to OBdata 0.44...

U5700 8 - PPVIN_P3V8AON - 12.3V 7 - PP5V_AON_P3V8AON - 5V 5 - P3V8AON_PVVC - 5V 12 - P3V8AON_PWR_EN_R - 4.5V

Lady's a2485 just stopped. No visible liquid damage to board 5volts 20mA not connected to battery, trackpad ppbus_aon 12.3v pp3v8_aon oscillating 2.5v to 3.4 avg 3.2v (low) I noticed U5700 has an erratic input voltage pp5v_s2_main 0.6v to 5v p5vs2tps_pwr_en 0.2v but Im going around in circles...

Macbook boots just fine with a new battery and will charge it. But when left for a day or two off charge and shutdown it flattens the battery and then won't boot. CmiZapper Battery Tool reports a drain of 90mA even when shutdown as cells drop below 3v each. This looks large to me when a...

Fans well clogged No visible evidence of liquid damage 20v 2a, battery is being charged no boot chime fans spin caps lock light toggles no internal LCD image or backlight no external video, also tried when internal LCD disconnected Tried good screen, still nothing. L8504 not blown Was able to...

Hello anyone there?

The voltage levels for the NANDS appear good. Doesn't a bad NAND normally develop a short that would pull these down? pp0v9_nand0 0.9v pp1v2_nand0 1.2v pp2v5_nand0 2.5v ppvin_p3v8nand0 3.8v I noticed ppvdd_ldo_nand0_ocarina is only 1.4v rather than schematics 2.5v Before the CD3217 negotiate...

I understand you are saying 3V3_S2 comes from the U8100 and there may be problems with that chip and that chip has a healthy power supply in PP3V8_AON_VDDMAIN. But is it being told to turn on? In FlexBV notes there is a list of things that come before "step 11 (Many rails appear now)". Is that...

Yes 3V3_S2 is 3.3v on the good board

But the asymmetry described in my post #6 is not present on the working board. The rom gets 3.3v no matter which channel is powered. Anyway do you suggest I replace U8100?

Ive just taken delivery of a locked identical board that gets to 20v. Ive just taken its CD3217s and I still get that asymmetry described in my post #6. So the rom only gets 3.3volts when charger on channel0 and 0.5v when on channel1. There are no voltages on inductors around U8100.

PP3V3_S2_UPC 0.58v PP1V25_S2 0v PP3V8_AON_VDDMAIN 3.8v

OK the original CD3217 back in their places. ppbus_aon 12.3v 3v8_aon 3.8v When charger connected to channel 0 pp3v3_upc0_ldo [which powers the ROM] only gets 3.3 volt when pp3v3_upc1_ldo sits at 0.4v when charger connected to channel 1 pp3v3_upc0_ldo [which powers the ROM] gets 0.4 volts...

Pressing power button when on charger [or on battery] would result in Apple logo for 2 seconds before shutoff. Original battery was not charging. Battery replaced, battery now charges. Given a good charge. Still only reaches Apple logo before shutoff. Corrosion on CF800, CF813 but DM voltages...

Ah thought left hand side CD3217 were replaceable with purchasable ones. Good job I kept originals. Im going to put them back and post status again!